The present inventions relate to a printing apparatus, more specifically, they relate to the printing apparatus having an erasing mechanism erasing a character, and being adapted to reprint an erased character string by an erase cancel command.
Most recent electronic typewriters and the like, are provided with a present position memory storing a present position of a print head and a print data memory storing a printed data inputted from a key-board in its control system, and including an erasing mechanism sequentially erasing the character string consisting of a set of printed characters in the counter printing direction with a correction ribbon by utilizing the data from said present position memory and print data memory according to operation of an erase command key on the key-board. For example, in U.S. Pat. No. 4,561,793, An Automatic Word Correcting System is disclosed.
When printing an article and the like on a print paper with the printing apparatus including such erasing mechanism, if the character string is erased by misoperation or the like, the character string must be reprinted.
For Example, U.S. Pat. No. 4,480,931 discloses a typewriter provided with an output buffer for storing data of the character string of about two lines, a correct buffer for storing the erased character string data, a key code register and other various registers and buffers. These are controlled to print a character or symbol corresponding to a character or symbol key operated, as well as to store the character or symbol data in the output buffer via the key code register, to erase the character indicated by the print head by operating an erase key on the key-board, to automatically erase serial character strings in the counter printing direction by using the erase key and a repeat key together, to store the erased character string data in the correct buffer, and when necessary, to automatically reprint the character string corresponding to the data stored in the correct buffer in the printing direction from the present position of the print head by operating a print key.
In the correct buffer, serial erased character data corresponding to about two lines can be stored, but it is not possible to store a plurality of character strings sequentially and sequentially.
In the typewriter disclosed in U.S. Pat. No. 4,480,531, when automatically erasing the serial character string by using the erase key and repeat key together, the character string, not required to be erased following the character string desired to be erased may be erased in excess by misoperation.
In this case, the character string erased by misoperation is printed again by character or symbol key operation, otherwise the erased character string is fully reprinted at the print positions from which they were previously erased and then only the misprinted character string is erased. These steps result in complicated operation and reduction of operating efficiency.
Also, when reprinting the character string erased by misoperation at the previous print position, the print head must be moved precisely at the head print position of the erased character string by means of a back space key or a space key before reprinting, thus causing complicated and time consuming reprint operation.
In such case as erasing two character strings and mutually exchanging the print positions to reprint, one of two character strings can be reprinted at the desired position, but the other character string must be printed by repeating the key input.
Also, when reprinting the data stored in the correct buffer and when there is a printed character at the print position of the character string to be reprinted, it must be reprinted after erasing the character in advance, thus causing complicated operation.
When reprinting the erased character string at the previous print position, since reprinting is allowed irrespective of presence or kind of operation of a printing mechanism after the erasing operation, a control for bringing the moved print head to correspond to the print position to be reprinted or a control program for reprinting is complicated.
Meanwhile, in U.S. Pat. No. 3,780,846, an Automatic Erasing Typewriter System designed to erase in a character, word and line unit for adding, correcting and erasing the character or word among which a desired one can be reprinted is disclosed.
However, (a) when the erase command is inputted, since character, word and line modes must be specified or "ERASE" and "ERASE and DELETE" modes must be specified, the number of mode is increased and the key operation is complicated. (b) Since bits for storing information such as "Useful information", "Symbol not appear" and so on are required in bytes of each character or symbol in the memory, a data construction of the memory is complicated and a necessary memory capacity is enlarged. (c) When erasing the character or word and moving it in a printing direction by a prescribed distance to reprint, a number of space code data must be inputted after erasing to reprint at the desired position. (d) After erasing the character or word, when the new character or word is printed at its position to reprint, since erase control and reprint control of the new character or word is not interlocked, the number of key operation is increased.
The first object of the present invention is to reprint partially or fully a character string erased wrongly by misoperation at original print positions.
The second object of the present invention is to reprint sequentially the desired character string among plural erased character strings at the desired space respectively with changed or unchanged disposition.
The third object of the present invention is to reprint sequentially the desired character string among plural erased character strings at the original space.
The fourth object of the present invention is to simplify the reprint control and operation for reprinting one or more erased character strings.